1. Field of the Invention
This invention relates to power factor correction. More specifically, this invention relates to computer controlled solid-state switching power factor correction.
2. Description of Related Art
A variety of techniques for power factor correction have been proposed and are well known in the art. Generally, these prior systems and techniques sense only one phase and switch, using contactor relays, all three phases at one time.
Although, the following may not necessarily be “prior art”, the reader is referred to the following U.S. patent documents for general background material. Each of these patent documents is hereby incorporated by reference in its entirety for the material contained therein.
U.S. Pat. No. 4,356,440 describes a discrete-time, closed loop power factor corrector system that control the coupling of a delta-connected switched capacitor array to a 3- or 4-wire power line which may have time-varying, unbalanced, inductive loads.
U.S. Pat. No. 4,417,194 describes an electric power generator system that includes a switched capacitor controlled induction generator adapted to provide power at a regulated voltage and frequency.
U.S. Pat. No. 4,493,040 describes a computer-controlled welding apparatus that includes a phase-controlled resistance welding circuit for selectively conducting pulses of a welding current to a workpiece and a control circuit for controlling the conduction of the welding circuit.
U.S. Pat. No. 5,134,356 describes a system and method for determining and providing reactive power compensation for an inductive load.
U.S. Pat. No. 5,180,963 describes an optically triggered solid-state switch and method for switching a high voltage electrical current.
U.S. Pat. No. 5,473,244 describes an apparatus for performing non-contacting measurements of the voltage, current and power levels of conductive elements such as wires, cables and the like, that includes an arrangement of capacitive sensors for generating a first current in response to variation in voltage of a conductive element.